IE 11 ignores style="display: none" in compatability mode

[jason iffrig]

It appears that styles such as display:none and visibility:hidden are ignored when running 3.6.4 with IE 11 in compatibility mode.

[Piotrek Koszuliński]

3.6.4 is not supported any more. IE11 support was added in CKEditor 4.3, however, I'm not sure what compatibility mode is in details (I assume it's IE5 QM). We tested CKEditor with standards Quirks Mode and IE5 Quirks Mode and from CKEditor 4.3.1 CKEditor will work on both of them (see #11182).

I checked that on IE11 on master this works in standards mode:

<p>ddd</p>

<p style="display: none;">ddd</p>

<p>ddd</p>

It does not work in IE5 QM, but in this mode we support only important features. Plus, I'm not even sure if it's possible to hide those elements.

[Jakub Ś]

NOTE: Compatibility mode is something different that QM. You can turn it on in IE->Tools->Compatibility View Settings or using <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />

The problem here is that this is IE issue. Try below code on plain HTML5 page with compatibility mode turned on:

<div style="margin: 20px; border:1px solid black; width:500px;" contenteditable="true">
<h2>Set compatibility mode using IE and display:none will not work.</h2>
<p>ddd</p>
<p style="display: none;">ddd</p>
<p>ddd</p>

Element will be visible as well.

This means there is nothing we can do and with is a "won't fix" issue.

NOTE: This seems to work with dispaly:none elements <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />. Perhaps you could use it as a workaround.